Apparatus and method for continuously granulating powder material

Abstract

An apparatus for continuously granulating powder material has a feeder for continuously supplying powder material, and a granulation vessel. The granulation vessel includes a granulation zone and a drying zone. The apparatus also has a spray nozzle disposed so as to be declined above the granulation zone for adding binder to the powder material, a perforated plate disposed below the granulation zone and the trying zone, an intermediate weir disposed between the granulation zone and the drying zone so as to provide a space between the intermediate weir and the perforated plate, an outlet weir disposed at an outlet side of the drying zone, and a heated air supplying device for supplying from below heated air to the granulation zone and the drying zone so as to form a fluidized bed of the material.

What is claimed is: 
     
       1. A method for continuously granulating powder material comprising the steps of: agitating and mixing powder material;   continuously supplying the agitated and mixed powder material to a granulation vessel which includes a granulation zone and a drying zone, said granulation vessel having side walls which are inclined at a predetermined angle so that an opening area thereof becomes larger toward its top end;   forming a fluidized bed in the granulation zone and the drying zone by letting heated air having a predetermined temperature flow upwardly through a perforated plate disposed below the granulation zone and the drying zone;   adding binder to the powder material in the fluidized bed in the granulation zone by a spray nozzle disposed above the granulation zone so that the powder material is granulated;   moving the granulated material by a piston flow from the granulation zone to the drying zone through a space having a predetermined height, the space being provided between the perforated plate and an intermediate weir which is disposed substantially vertically between the granulation zone and the drying zone;   drying the granulated material in the drying zone by using the heated air; and   discharging the dried granulated material to outside of the granulation vessel by letting the material overflow an outlet weir having a predetermined height and being disposed at an outlet side of the drying zone.   
     
     
       2. A method for continuously granulating powder material according to claim 1, wherein said method further comprises the step of adding edible fats and oils to the powder material in the granulating zone or an upstream side before the granulating zone.